Andrew Emond, a Montreal-based photographer, amateur geographer, and DIY gonzo spelunker of the city's sewers and lost rivers, has just re-launched his excellent website, Under Montreal. The revamped site now comes complete with a fascinating, interactive map of the city's subterranean streams, documenting Montreal's invisible rivers for all to see.

"Beneath Montreal, Canada," Emond's site explains, "lies a sewer system encompassing a combined distance of over 5,000 kilometers. With some sections dating back to 1832, this network offers a unique framework through which one can explore a city and its history." These buried waterways—and the infrastructure that holds them—are thus a history lesson in spatial form, Emond suggets.

Emond describes its extraordinary geological formations as a kind of quasi-natural cave in the making: "I've encountered calcite deposits inside sewers in the past. Stalactites, stalagmites, 'soda straws' and flowstones are all to be found in just about any sewer or storm drain that is more than a decade or so old. Caused partially by the limestone in cement, these formations can help turn a run-of-the-mill system into something quite wonderful."

But the Cote St. Paul system takes it to another level: "In fact," Emond adds, "I've never seen anything else like it... For roughly 100 meters, the walls of this century-old sewer make for a breathtaking spectacle. Nature has completely taken over to the point where you're easily tricked into believing you're not inside a man-made structure anymore. Instead, you are in a cave deep beneath the surface of the earth in some exotic country."

In fact, I'm reminded of an amazing description in Peter Ackroyd's recommended (and refreshingly short) book, Under London, where he describes the tunnels beneath the city as kind of tropical wonderland, a Borneo of the subcity.

Referring to the humid sewers and overgrown streams of London, Ackroyd suggests that any attempt to describe the city's underside, its shadow self, "might be a narrative from the swamps of Borneo rather than the City of London."

The underground chambers are compared to cathedrals, complete with pillars and buttresses, arches and crypts. One visitor, discovering an archway through which a cataract tumbled, remarked that it was as fantastic a scene as "a dream of a subterranean monastery." The travelers walk along tunnels that may reach a height of 17 feet, the cool tainted water lapping at about knee-height around their waders. Many are disconcerted by the pull of the water, and feel disoriented; they lose their equilibrium. They feel the sediment beneath their feet, as if they were walking on a beach at low tide. Great iron doors loom up at intervals, actings as valves. The noise of roaring water, somewhere in the distance, can generally be heard. It is the sound of cataracts and waterfalls.

This rush—both of adrenalin and of distant water cascading down artificial waterfalls—is something Andrew Emond is quite familiar with, having stood amidst these intersections of rivers and cataracts armed only with a flashlight, boots, and digital camera.

Emond, of course, is already widely known for his work. He was featured in the recent film, Lost Rivers, for example, which was very recently released on DVD by Catbird Productions (and is worth seeking out).

That film, a long look at attempts around the world to "daylight" lost urban rivers—that is, to rescue and uncover them from beneath the pavement—spends several scenes exploring Montreal alongside Emond, making it abundantly clear how a city's history can be found in this, least likely of places.

After all, Emond's work is motivated not just by the thrill of it all, but by a deep interest in the city's historical geography.

Like his compatriot, Toronto's Michael Cook, author of Vanishing Point, who also treats his long journeys underground as a kind of cartographic ground-truthing of the city's riverine past, Emond is literally casting light on the forgotten, buried landscapes of the city, from its earliest colonial days to its industrial heyday.

We begin, for instance, with some historical context and old maps of the city, before progressing horizontally up the drainage pipes, passing beneath the landscape into Emond's own speleology of the caves and tunnels beneath the streets.

In fact, the Rivière St. Pierre actually passes underneath another canal, turning it into a delirious, M.C. Escher-like knot of waterways passing beneath waterways, more topology than municipal infrastructure.

"In a golf course to the west of downtown Montreal," he writes, "you'll find the last remaining portion of Rivière Saint-Pierre that still exists above ground. 200 meters are all that are left of a river system that once flowed freely over the landscape. The rest of it's been retrofitted into the city's sewer system or lost entirely."

Lost, that is, yet Emond has made it a point to help uncover this dimension of the city for us to see.

And what he shows us is extraordinary, like some shining and mysterious portal to another world.

Divorced of their historic context, Emond's photos quickly take on the narrative feel of an unreleased Andrei Tarkovsky film.

Seen purely as urban sci-fi, these photos suggest a gang of anonymous urban explorers marching ahead through the crossing streams, a light-free zone of reservoirs and tombs.

We watch as human beings—almost always in the same Caspar David Friedrich-like pose, seen from behind as so-called Rückenfiguren looking out at some beautifully strange and intimidating landscape—wander through this maze of strangely compressed spaces, following echoes, ducking beneath monumental overhangs and arched entryways.

Always pressing forward, they wander on, further and further up toward the source of these underground waters.

Turning corners, taking photographs, unsure of what they'll find.

In any case, Emond's revamped site is worth a long look, especially for the detailed historical context supplied for each river and stream; go check it out, and drop any of your own underground photos in the comments, below. [Under Montreal]